Acta Astronautica
Papers 10441
1 page of 1,045 pages (10.4k results)
Abstract Few databases exist for the research on the ignition or combustion of moving micron-sized Mg particles in CO2. In this study, the ignition and combustion characteristics of moving micron-sized Mg particles in CO2 were examined with a closed high-temperature furnace and a pneumatic ejection device. The ignition and combustion processes were captured and recorded with a high-speed camera. The condensed products were collected with a water-cooled probe and analyzed with a transmission elec...
Abstract Cables are widely used because of their light weight and wide range of arrangement. To guarantee successful deployment and retraction of cable-driven mechanisms, this paper proposes a novel cable-winding device to fulfil particular requirements of a space mission, such as a large driving force output, large cable displacement, and high reliability. The device consists of three parts: the transmission assembly, cable arrangement assembly, and redundancy motor assembly. The transmission a...
Abstract In this article, a magnetic control without attitude determination for spinning spacecraft is presented. The control only uses magnetorquers as actuators and sun-sensors and magnetometers as sensors. An equilibrium angular velocity is reached by using two magnetic moments at the same time; the first one is a B-dot control that produces a despinning torque based in magnetic measurements; the second one produces a spinning torque using an inertial reference, such as the sun’s direction as...
Abstract The paper compares two variants of re-orbiting space debris objects from the geosynchronous (GEO) region. Under the first re-orbiting variant, a spacecraft-collector transfers between target objects (87 upper stages). Each object is re-orbited into a disposal orbit (DO) using special thruster de-orbiting kits (TDK) which are placed on space debris objects by the collector. Under the second variant, the object is pushed to a DO by the collector itself, which then moves to a new space deb...
Abstract The chemical nonequilibrium mathematical model is built to investigate the effect of the air species model on the heat flux, based on Navier-Stokes equations, the Gupta chemical kinetics model and air species models, including the five-species model, the seven-species model and the eleven-species model. The code is programmed in FORTRAN, and verified by making a comparison with the data in the literature. A good deal of calculations under different cases are completed to obtain differen...
Abstract Numerical simulations were performed to study diffraction of a cellular detonation wave over a 90 ∘ cylindrical convex wall. The dynamics of this diffraction phenomenon was described by the two-dimensional reactive Euler equations with a detailed hydrogen/oxygen chemistry model and solved numerically by using the adaptive mesh refinement code AMROC. The present numerical observations indicate that the continuous variation trend of area divergence ratio caused by the curved convex wall c...
Abstract The combination of a solar array and a communication antenna can reduce the entire mass, physical size, and cost in space applications. Currently, related studies mainly focus on the combination of the two structures on one flat plate structure (FPS). Compared with the FPS, a paraboloid structure has lower surface density and higher conversion efficiency. Therefore, the novel design of a space large deployable paraboloid structure with power and communication integration (SSPCI) is prop...
Abstract The gyroelastic body refers to a flexible structure with distributed angular momentum exchange devices (AMEDs), such as the momentum wheels (MWs) or the control moment gyros (CMGs). The amplitude or the direction of the angular momentum of the rotors in the AMEDs can be changed to produce torques for vibration suppression of the flexible structure. In order to take full advantage of the AMEDs on the flexible structure, the AMEDs are also used for energy storage in this study, thus, an i...
Abstract An experimental study was conducted to investigate the thermal ignition and combustion characteristics of liquid droplet of ammonium dinitramide based liquid propellant in different oxidizing gas atmospheres under different on-load voltages. The oxidizing gases included air, O2, N2O and NO. The ignition and combustion processes were recorded synchronously by two high speed cameras to catch the directly recorded images and schlieren images respectively. In order to explore the ignition a...
Abstract The advection diffusion model was evaluated for gas transport within a packed bed of lunar JSC-1A regolith simulant at low to medium total pressures over three flow regimes: (1) the slip flow regime (2) the transition regime and (3) the Knudsen regime. These regimes are pertinent to the design of H2O extraction devices for in-situ resource utilization, sampling missions, and surface science. Experimentation was conducted over a range of average pressures of 100 to 25,000 Pa, correspondi...
Top fields of study
Remote sensing
Control theory